This application claims priority to German Patent Application 10111877.5, filed Mar. 10, 2001, which is hereby incorporated by reference, in their entirety. All references cited below, including patents, patent applications and scientific journals and books also are herein incorporated by reference in their entirety.
1. Field of Invention
This invention relates to novel imidazolidine derivatives, their preparation, their use and pharmaceutical preparations comprising them.
2. Description of Related Art
The integrins are a group of adhesion receptors, which play an important role in cell-cell-binding and cell-extracellular matrix-binding processes. They have an xcex1xcex2-heterodimeric structure and exhibit a wide cellular distribution and a high extent of evolutive conservation. The integrins include, for example, the fibrinogen receptor on platelets, which interacts especially with the RGD sequence of fibrinogen, or the vitronectin receptor on osteoclasts, which interacts especially with the RGD sequence of vitronectin or of osteopontin. The integrins are divided into three major groups, the xcex22 subfamily containing the representatives LFA-1, Mac-1 and p150/95, which are responsible in particular for cell-cell interactions of the immune system, and the subfamilies xcex21 and xcex23, whose representatives mainly mediate cell adhesion to components of the extracellular matrix (Ruoslahti, Annu. Rev. Biochem., 57:375 (1988)). The integrins of the xcex21 subfamily, also called VLA proteins (very late (activation) antigen), include at least six receptors, which interact specifically with fibronectin, collagen and/or laminin as ligands. Within the VLA family, the integrin VLA-4 (xcex14xcex21) is atypical insofar as it is mainly restricted to lymphoid and myeloid cells and is responsible in these for cell-cell interactions with a large number of other cells. VLA-4 mediates, for example, the interactions of T and B lymphocytes with the heparin II-binding fragment of human plasma fibronectin (FN). The binding of VLA-4 with the heparin II-binding fragment of the plasma fibronectin is based especially on an interaction with an LDVP sequence. In contrast to the fibrinogen or vitronectin receptor, VLA-4 is not a typical RGD-binding integrin (Kilger and Holzmann, J. Mol. Meth., 73:347 (1995)).
The leukocytes circulating in the blood normally exhibit only a low affinity for the vascular endothelial cells, which line the blood vessels. Cytokines, which are released from inflamed tissue, cause the activation of endothelial cells and thus, the expression of a large number of cell surface antigens. These include, for example, the adhesion molecules ELAM-1 (endothelial cell adhesion molecule-1; also designated as E-selectin), which, inter alia, binds neutrophils, ICAM-1 (intercellular adhesion molecule-1), which interacts with LFA-1 (leukocyte function-associated antigen 1) on leukocytes, and VCAM-1 (vascular cell adhesion molecule-1), which binds various leukocytes, inter alia lymphocytes (Osborn et al., Cell, 59:1203 (1989)). VCAM-1 is, like ICAM-1, a member of the immunoglobulin gene superfamily. VCAM-1 (first known as INCAM-110) was identified as an adhesion molecule, which is induced on endothelial cells by inflammatory cytokines, such as TNF and IL-1 and lipopolysaccharides (LPS). Elices et al., Cell, 60:577 (1990) showed that VLA-4 and VCAM-1 form a receptor-ligand pair which mediates the attachment of lymphocytes to activated endothelium. The binding of VCAM-1 to VLA-4 does not take place due to an interaction of the VLA-4 with an RGD sequence, such a sequence is not contained in VCAM-1 (Bergelson et al., Current Biology, 5:615 (1995)). In addition, VLA-4 occurs, however, on other leukocytes, and the adhesion of leukocytes other than lymphocytes is also mediated via the VCAM-1/VLA-4 adhesion mechanism. VLA-4 thus represents an individual example of a xcex21-integrin receptor which, via the ligands VCAM-1 and fibronectin, plays an important role both in cell-cell interactions and in cell-extracellular matrix interactions.
The cytokine-induced adhesion molecules play an important role in the recruitment of leukocytes into extravascular tissue regions. Leukocytes are recruited into inflammatory tissue regions by cell adhesion molecules, which are expressed on the surface of endothelial cells, and serve as ligands for leukocyte cell surface proteins or protein complexes (receptors) (the terms ligand and receptor also can be used vice versa). Leukocytes from blood must first adhere to endothelial cells before they can migrate into the synovium. Since VCAM-1 binds to cells, which carry the integrin VLA-4 (xcex14xcex21), such as eosinophils, T and B lymphocytes, monocytes or neutrophils, it and the VCAM-1/VLA-4 mechanism have the function of recruiting cells of this type from the bloodstream into areas of infection and inflammatory foci (Elices et al., Cell, 60:577 (1990); Osborn, Cell, 62:3 (1990); Issekutz et al., J. Exp. Med., 183:2175 (1996)).
The VCAM-1/VLA-4 adhesion mechanism has been connected with a number of physiological and pathological processes. Apart from by cytokine-induced endothelium, VCAM-1 is additionally expressed, inter alia, by the following cells: myoblasts, lymphoid dendritic cells and tissue macrophages, rheumatoid synovium, cytokine-stimulated neural cells, parietal epithelial cells of Bowman""s capsule, the renal tubular epithelium, inflamed tissue during heart and kidney transplant rejection, and by intestinal tissue in graft versus host disease. VCAM-1 is also found to be expressed on those tissue areas of the arterial endothelium, which correspond to early atherosclerotic plaques of a rabbit model. In addition, VCAM-1 is expressed on follicular dendritic cells of human lymph nodes and is found on stroma cells of the bone marrow, for example in the mouse. The latter finding points to a function of VCAM-1 in B-cell development. Apart from on cells of hematopoetic origin, VLA-4 is also found, for example, on melanoma cell lines, and the VCAM-1/VLA-4 adhesion mechanism is connected with the metastasis of such tumors (Rice et al., Science, 246:1303 (1989)).
The main form, wherein VCAM-1 occurs in vivo on endothelial cells and which is the dominant form in vivo is designated as VCAM-7D and carries seven immunoglobulin domains. The domains 4, 5 and 6 are similar in their amino acid sequences to the domains 1, 2 and 3. In a further form consisting of six domains, designated here as VCAM-6D, the fourth domain is removed by alternative splicing. VCAM-6D can also bind VLA-4-expressing cells.
Further details concerning VLA-4, VCAM-1, integrins and adhesion proteins are found, for example, in the articles by Kilger and Holzmann, J. Mol. Meth., 73:347 (1995); Elices, Cell Adhesion in Human Disease, Wiley, Chichester 1995, p. 79; Kuijpers, Springer Semin. Immunopathol., 16:379 (1995).
On account of the role of the VCAM-1/VLA-4 mechanism in cell adhesion processes, which are of importance, for example, in infections, inflammation or atherosclerosis, it has been attempted by means of interventions in these adhesion processes to control disorders, in particular, for example, inflammations (Osborn et al., Cell, 59:1203 (1989)). A method of doing this is the use of monoclonal antibodies which are directed against VLA-4. Monoclonal antibodies (mABs) of this type, which as VLA-4 antagonists block the interaction between VCAM-1 and VLA-4, are known. Thus, for example, the anti-VLA-4 mABs HP2/1 and HP1/3 inhibit the attachment of VLA-4-expressing Ramos cells (B-cell-like cells) to human umbilical cord endothelial cells and to VCAM-1-transfected COS cells. Likewise, the anti-VCAM-1 mAB 4B9 inhibits the adhesion of Ramos cells, Jurkat cells (T-cell-like cells) and HL60 cells (granulocyte-like cells) to COS cells transfected with genetic constructs which cause VCAM-6D and VCAM-7D to be expressed. In vitro data with antibodies which are directed against the xcex14 subunit of VLA-4 show that the adhesion of lymphocytes to synovial endothelial cells is blocked, an adhesion which plays a role in rheumatoid arthritis (van Dinther-Janssen et al., J. Immunol., 147:4207 (1991)).
In vivo experiments have shown that experimental autoimmune encephalomyelitis can be inhibited by anti-xcex14 mAB. The migration of leukocytes into an inflammatory focus is likewise blocked by a monoclonal antibody against the xcex14 chain of VLA-4. The influencing of the VLA-4-dependent adhesion mechanism using antibodies has also been investigated in an asthma model in order to investigate the role of VLA-4 in the recruitment of leukocytes into inflamed lung tissue (WO-A-93/13798). The administration of anti-VLA-4 antibodies inhibited the late-phase reaction and the airway hyperreaction in allergic sheep. The importance of VLA-4 as a target for the treatment of asthma is discussed in detail in Metzger, Springer Semin. Immunopathol., 16:467 (1995).
The VLA-4-dependent cell adhesion mechanism was also investigated in a primate model of inflammatory bowel disease (IBD). In this model, which corresponds to ulcerative colitis in man, the administration of anti-xcex14 antibodies resulted in a significant reduction of the acute inflammation.
Moreover, it was possible to show that the VLA-4-dependent cell adhesion plays a role in the following clinical conditions including the following chronic inflammatory processes: rheumatoid arthritis (Cronstein and Weismann, Arthritis Rheum., 36:147 (1993); Elices et al., J. Clin. Invest., 93:405 (1994)), diabetes mellitus (Yang et al., Proc. Natl. Acad. Sci. USA, 90:10494 (1993), systemic lupus erythematosus (Takeuchi et al., J. Clin. Invest., 92:3008 (1993)), allergies of the delayed type (type IV allergy) (Elices et al., Clin. Exp. Rheumatol., 11:S77 (1993)), multiple sclerosis (Yednock et al., Nature, 356:63 (1992)), malaria (Ockenhouse et al., J. Exp. Med., 176:1183 (1992)), atherosclerosis (O""Brien et al., J. Clin. Invest., 92:945 (1993); Shih et al., Circ. Res., 84:345 (1999)), transplantation (Isobe et al., Transplantation Proceedings, 26:867 (1994)), various malignancies, for example melanoma (Renkonen et al., Am. J. Pathol., 140:763 (1992)), lymphoma (Freedman et al., Blood, 79:206 (1992)) and others (Albelda et al., J. Cell Biol., 114:1059 (1991)).
The interaction of VLA-4 with VCAM-1 and fibronectin is connected with some pathophysiological processes in cardiovascular diseases. In an in vitro cell system, infiltrated neutrophils inhibit the cell contraction (negative inotropy) of cardiomyocytes by 35%. It was possible to inhibit this negative inotropic action of neutrophils by an anti-xcex14 antibody, but not by an anti-CD 18 antibody (Poon et al., Circ. Res., 84:1245 (1999)). The importance of VLA-4 in the pathogenesis of atherosclerosis was shown in a mouse model of atherosclerosis. Thus, the CS-1 peptide, which is directed against the binding site of VLA-4 on fibronectin, inhibits the recruitment of leukocytes and the accumulation of fat in the aorta and thus, the formation of atherosclerotic plaques in atherogenically fed LDL receptor knockout mice (Shih et al., Circ. Res., 84:345 (1999)). Using the same CS-1 peptide, it was furthermore possible to show in a heterotopic heart transplantation model in the rabbit that the formation of a transplant vasculopathy can be significantly decreased by the blockade of the interaction of VLA-4 and fibronectin (Molossi et al., J. Clin. Invest., 95:2601 (1995)).
Blocking of VLA-4 by suitable antagonists, thus, offers effective therapeutic possibilities of treating, for example, in particular various inflammatory conditions including asthma and IBD. The particular relevance of VLA-4 antagonists for the treatment of rheumatoid arthritis results here, as already stated, from the fact that leukocytes from the blood must first adhere to endothelial cells before they can migrate into the synovium, and that the VLA-4 receptor plays a role in this adhesion. The fact that VCAM-1 is induced on endothelial cells by inflammatory agents (Osborn, Cell, 62:3 (1990); Stoolman, Cell, 56:907 (1989)), and the recruitment of various leukocytes into areas of infection and inflammatory foci has already been discussed above. T cells adhere to activated endothelium here mainly via the LFA-1/ICAM-1 and VLA-4/VCAM-1 adhesion mechanisms (Springer, Cell, 76:301 (1994)). On most synovial T cells, the binding capacity of VLA-4 for VCAM-1 is increased in rheumatoid arthritis (Postigo et al., J. Clin. Invest., 89:1445 (1992)). In addition, an increased adhesion of synovial T cells to fibronectin has been observed (Laffon et al., J. Clin. Invest., 88:546 (1991); Morales-Ducret et al., J. Immunol., 149:1424 (1992)). Thus, VLA-4 is upregulated both with respect to its expression and with respect to its function on T lymphocytes of the rheumatoid synovial membrane. The blocking of the binding of VLA-4 to its physiological ligands VCAM-1 and fibronectin makes possible an effective prevention or alleviation of articular inflammatory processes. This is also confirmed by experiments with the antibody HP2/1 on Lewis rats with adjuvant arthritis, in which an effective disease prevention was observed (Barbadillo et al., Springer Semin. Immunopathol., 16:427 (1995)). CS-1 peptidomimetics, which contain an aspartic acid unit or a derivative thereof in the molecule and which inhibit the binding of VLA-4 to the CS-1 sequence of the matrix protein fibronectin, are described in WO-A-00/02903. Thus, VLA-4 is an important therapeutic target molecule.
The abovementioned VLA-4 antibodies and the use of antibodies as VLA-4 antagonists are described in the patent applications WO-A-93/13798, WO-A-93/15764, WO-A-94/16094, WO-A-94/17828 and WO-A-95/19790. The patent applications WO-A-94/15958, WO-A-95/15973, WO-A-96/00581, WO-A-96/06108 and WO-A-96/20216 describe peptide compounds as VLA4 antagonists. The use of antibodies and peptide compounds as pharmaceuticals, however, is afflicted with disadvantages, such as, for example, lack of oral availability, easy degradability or immunogenic action on long-term administration, and thus, there is a need for VLA-4 antagonists having a favorable property profile for use in the therapy and prophylaxis of various disease conditions.
WO-A-95/14008, WO-A-93/18057, U.S. Pat. Nos. 5,658,935, 5,686,421, 5,389,614, 5,397,796, 5,424,293 and 5,554,594 describe substituted 5-membered ring heterocycles, which have an amino, amidino or guanidino function at the N-terminal end of the molecule and which show platelet aggregation-inhibiting actions. EP-A-796 855 further describes heterocycles, which are inhibitors of bone resorption. EP-A-842 943, EP-A-842 945 and EP-A-842 944 describe compounds from these series and further compounds that surprisingly inhibit leukocyte adhesion and are VLA-4 antagonists. EP-A-903 353, EP-A-905 139, EP-A-918 059, U.S. Pat. Nos. 6,034,238, 6,331,552 B, WO-99/23063, WO-A-99/24398, WO-A-99/54321 and WO-A-99/60015 further describe compounds which inhibit leukocyte adhesion and are VLA-4-antagonists. The properties of these compounds, however, are still not satisfactory in various respects and there is a need for compounds having a further improved property profile. EP-A-918 059 and U.S. Pat. No. 6,331,552 B mentions, inter alia, imidazolidine derivatives, wherein the imidazolidine ring is bonded via its 1-position to the carbon atom in the 2-position of a 2-(cycloalkylalkyl)acetylamino unit or a 2-isobutylacetylamino unit. Not specifically disclosed, however, are the imidazolidine derivatives of formula I of the present invention, which are distinguished by their advantageous property profile and in particular by their markedly increased potency.
The present invention relates to a compound of formula I, 
wherein
A is cyclopropylmethyl- or isobutyl;
E is xe2x80x94COxe2x80x94R6, xe2x80x94COxe2x80x94H or xe2x80x94CH2xe2x80x94Oxe2x80x94R7;
Z is oxygen or sulfur;
R1 is hydrogen or methyl;
R2 is phenyl, pyridyl or (C1-C4)-alkyl, where the alkyl residue can be substituted by one or more fluorine atoms and the phenyl residue can be substituted by one or more identical or different substituents selected from the group consisting of (C1-C4)-alkyl, (C1-C4)-alkoxy, methylenedioxy, ethylenedioxy, halogen, trifluoromethyl and trifluoromethoxy;
R3 and R4 are methyl or trifluoromethyl;
R5 is hydrogen or (C1-C4)-alkyl, where the alkyl residue can be substituted by one or more fluorine atoms;
R6 is hydroxyl, (C1-C10)-alkoxy, phenyl-(C1-C8)-alkoxy, phenyloxy, (C1-C8)-alkylcarbonyloxy-(C1-C6)-alkoxy, phenylcarbonyloxy-(C1-C6)-alkoxy, phenyl-(C1-C6)-alkylcarbonyloxy-(C1-C6)-alkoxy, (C1-C8)-alkoxycarbonyloxy-(C1-C6)-alkoxy, phenyloxycarbonyloxy-(C1-C6)-alkoxy, phenyl-(C1-C6)-alkoxycarbonyloxy-(C1-C6)-alkoxy, amino, mono((C1-C10)-alkyl)amino or di((C1-C10)-alkyl)amino;
R7 is hydrogen or (C1-C4)-alkyl;
in all its stereoisomeric forms and mixtures thereof in all ratios,
or its physiologically acceptable salts.
The present invention also relates to a process for the preparation of compounds of formula I, which comprises reacting a compound of formula II with a compound of formula III 
where A, E, Z, R1, R2, R3, R4 and R5 are as defined in formula I or functional groups are present in protected form or in the form of precursors, and where G is hydroxycarbonyl, (C1-C6)-alkoxycarbonyl or activated carboxylic acid derivatives.
The present invention further embodies pharmaceutical compositions, which comprise one or more compounds of formula I and/or derivatives thereof and/or physiologically acceptable salts thereof and a pharmaceutical acceptable carrier.
The present invention also relates to methods of treating, for example, inflammation, arthritis, rheumatoid arthritis, polyarthritis, inflammatory bowel disease, systemic lupus erythematosus, multiple sclerosis, inflammatory diseases of the central nervous system, asthma, allergies, cardiovascular diseases, atherosclerosis, myocardial infarct, the acute coronary syndrome, stroke, restenoses, diabetes, damage to organ transplants, immune diseases, autoimmune diseases, tumor growth, tumor metastasis, or malaria comprising administering to a mammal in need thereof a effective amount of a compound of formula I, or a derivative thereof, or a pharmaceutically acceptable salt thereof.
The present invention further relates to a method for cardioprotection or secondary prophylaxis of stroke, and a method of inhibiting the adhesion and/or migration of leukocytes, or inhibiting the VLA-4 receptor comprising administering to a mammal in need thereof a effective amount of a compound of formula I, or a derivative thereof, or a pharmaceutically acceptable salt thereof.
The present invention relates to compounds of formula I, 
wherein
A is cyclopropylmethyl- or isobutyl;
E is xe2x80x94COxe2x80x94R6, xe2x80x94COxe2x80x94H or xe2x80x94CH2xe2x80x94Oxe2x80x94R7;
Z is oxygen or sulfur;
R1 is hydrogen or methyl;
R2 is phenyl, pyridyl or (C1-C4)-alkyl, where the alkyl residue can be substituted by one or more fluorine atoms and the phenyl residue can be substituted by one or more identical or different substituents selected from the group consisting of (C1-C4)-alkyl, (C1-C4)-alkoxy, methylenedioxy, ethylenedioxy, halogen, trifluoromethyl and trifluoromethoxy;
R3 and R4 are methyl or trifluoromethyl;
R5 is hydrogen or (C1-C4)-alkyl, where the alkyl residue can be substituted by one or more fluorine atoms;
R6 is hydroxyl, (C1-C10)-alkoxy, phenyl-(C1-C8)-alkoxy, phenyloxy, (C1-C8)-alkylcarbonyloxy-(C1-C6)-alkoxy, phenylcarbonyloxy-(C1-C6)-alkoxy, phenyl-(C1-C6)-alkylcarbonyloxy-(C1-C6)-alkoxy, (C1-C8)-alkoxycarbonyloxy-(C1-C6)-alkoxy, phenyloxycarbonyloxy-(C1-C6)-alkoxy, phenyl-(C1-C6)-alkoxycarbonyloxy-(C1-C6)-alkoxy, amino, mono((C1-C10)-alkyl)amino or di((C1-C10)-alkyl)amino;
R7 is hydrogen or (C1-C4)-alkyl;
in all their stereoisomeric forms and mixtures thereof in all ratios,
and their physiologically acceptable salts.
Alkyl residues can be straight-chain or branched, whether they carry substituents or occur as substituents of other residues, for example, in fluoroalkyl residues, alkoxy residues or alkoxycarbonyl residues. Alkyl residues include, for example, methyl, ethyl, n-propyl, isopropyl (=1-methylethyl=iC3H7), n-butyl, isobutyl (=2-methylpropyl), sec-butyl (=1-methylpropyl), tert-butyl (=1,1-dimethylethyl), n-pentyl, isopentyl, tert-pentyl, neopentyl, n-hexyl, 3-methylpentyl, isohexyl, neohexyl, n-heptyl, 2,3,5-trimethylhexyl, n-octyl, n-nonyl, or n-decyl. Preferred alkyl residues are selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl. In alkyl residues, one or more, (e.g., 1, 2, 3, 4 or 5), hydrogen atoms can be substituted by fluorine atoms. Examples of such fluoroalkyl residues are trifluoromethyl, 2,2,2-trifluoroethyl, pentafluoroethyl, heptafluoroisopropyl. Substituted alkyl residues, for example phenylalkyl residues or fluoroalkyl residues, can be substituted in any desired positions.
Phenyl residues can be unsubstituted or mono- or polysubstituted (e.g. mono-, di-, tri-, tetra- or pentasubstituted) by identical or different substituents. Preferably, a phenyl residue carries one or two identical or different substituents, if it is substituted. This also applies to substituted phenyl residues in groups, such as phenylalkyl, phenylcarbonyl, and other substituted phenyl residues described herein. Phenylalkyl residues are, for example, benzyl, 1-phenylethyl or 2-phenylethyl, and preferably benzyl, all of which also can be substituted.
In monosubstituted phenyl residues, the substituent can be substituted in the 2-position, the 3-position or the 4-position. Disubstituted phenyl residues can be substituted in the 2,3-position, 2,4-position, 2,5-position, 2,6-position, 3,4-position or 3,5-position. In trisubstituted phenyl residues, the substituents can be substituted in the 2,3,4-position, 2,3,5-position, 2,4,5-position, 2,4,6-position, 2,3,6-position or 3,4,5-position. If a phenyl residue carries substituents from the group consisting of methylenedioxy (xe2x80x94Oxe2x80x94CH2xe2x80x94Oxe2x80x94) and ethylenedioxy (xe2x80x94Oxe2x80x94CH2xe2x80x94CH2xe2x80x94Oxe2x80x94), it preferably carries only one substituent from this group (if desired in addition to other substituents).
Substituted phenyl residues, which can represent R2, include, for example, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 2,3-dimethylphenyl, 2,4-dimethylphenyl, 2,5-dimethylphenyl, 2,6-dimethylphenyl, 3,4-dimethylphenyl, 3,5-dimethylphenyl, 2,4,5-trimethylphenyl, 2,4,6-trimethylphenyl, 3,4,5-trimethylphenyl, 2-(n-butyl)phenyl, 3-(n-butyl)phenyl, 4-(n-butyl)phenyl, 2-isobutylphenyl, 3-isobutylphenyl, 4-isobutylphenyl, 3-tert-butylphenyl, 4-tert-butylphenyl, 2-methoxyphenyl, 3-methoxyphenyl, 4-methoxyphenyl, 2,3-dimethoxyphenyl, 2,4-dimethoxyphenyl, 2,5-dimethoxyphenyl, 2,6-dimethoxyphenyl, 3,4-dimethoxyphenyl, 3,5-dimethoxyphenyl, 2,4,5-trimethoxy-phenyl, 2,4,6-trimethoxyphenyl, 3,4,5-trimethoxyphenyl, 2-(n-butoxy)phenyl, 3-(n-butoxy)phenyl, 4-(n-butoxy)phenyl, 2-isobutoxyphenyl, 3-isobutoxyphenyl, 4-isobutoxyphenyl, 2-tert-butoxyphenyl, 3-tert-butoxyphenyl, 4-tert-butoxyphenyl, 2,3-methylenedioxyphenyl, 3,4-methylenedioxyphenyl, 2,3-ethylenedioxyphenyl, 3,4-ethylenedioxyphenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2,3-difluorophenyl, 2,4-difluorophenyl, 2,5-difluorophenyl, 2,6-difluorophenyl, 3,4-difluorophenyl, 3,5-difluorophenyl, 2,4,5-trifluorophenyl, 2,4,6-trifluorophenyl, 3,4,5-trifluorophenyl, 2,3,5,6-tetrafluorophenyl, 2,3,4,5,6-pentafluorophenyl, 2-chloro-phenyl, 3-chlorophenyl, 4-chlorophenyl, 2,3-dichlorophenyl, 2,4-dichlorophenyl, 2,5-dichlorophenyl, 2,6-dichlorophenyl, 3,4-dichlorophenyl, 3,5-dichlorophenyl, 2-bromophenyl, 3-bromophenyl, 4-bromophenyl, 3-iodophenyl, 4-iodophenyl, 2-trifluoromethylphenyl, 3-trifluoromethylphenyl, 4-trifluoromethylphenyl, 3,4-bis-(trifluoromethyl)phenyl, 3,5-bis(trifluoromethyl)phenyl, 2-trifluoromethoxyphenyl, 3-trifluoromethoxyphenyl, or 4-trifluoromethoxyphenyl, etc. In substituted phenyl residues, also different substituents can be present in any desired combination, such as, for example, in the residues 3-methoxy-4-methylphenyl, 4-fluoro-3-methoxyphenyl, 3-fluoro-4-methoxyphenyl, 3,5-difluoro-4-methoxyphenyl, 3-fluoro-4,5-methylenedioxyphenyl, 3-fluoro-4,5-ethylenedioxyphenyl, 2-chloro-3-methylphenyl, 3-chloro-4-methylphenyl, or 3-chloro-4-fluorophenyl, etc.
Halogen is selected from the group consisting of fluorine, chlorine, bromine or iodine, preferably fluorine or chlorine.
Pyridyl is selected from the group consisting of 2-pyridyl, 3-pyridyl and 4-pyridyl. The nitrogen atom also can be oxidized in pyridyl residues and the corresponding compound of formula I can be present as a pyridine N-oxide, which is also encompassed in the present invention.
Physiologically acceptable salts of the compounds of formula I are, in particular, non-toxic or pharmaceutically utilizable salts. Compounds of formula I, which contain acidic groups (e.g., a carboxylic acid group representing the group E), can be present as alkali metal salts or alkaline earth metal salts (e.g., sodium salts, potassium salts, magnesium salts and calcium salts), or as ammonium salts (e.g., salts with physiologically acceptable quaternary ammonium ions and acid addition salts with ammonia and physiologically acceptable organic amines, for example, methylamine, ethylamine, triethylamine, 2-hydroxy-ethylamine, tris(2-hydroxyethyl)amine, xcex1,xcex1,xcex1-tris(hydroxymethyl)methylamine (tromethamine) or amino acids (e.g., basic amino acids)). Salts may comprise an acidic compound of formula I and an organic amine in a ratio of 1:1 or about 1:1 or in another ratio. For example, the acidic compound of formula I and the organic amine may be in a ratio of from about 1:0.5 to about 1:4 (i.e., 1 molecule of formula I per 0.5 to 4 molecules of the amine), and particularly in a ratio of from about 1:0.5 to about 1:2 (i.e., 1 molecule of formula I per 0.5 to 2 molecules of the amine).
Compounds of formula I, which contain basic groups (e.g., a pyridyl group), can be present as acid addition salts. Examples of acid addition salts include salts with inorganic acids, for example, hydrochloric acid, sulfuric acid or phosphoric acid; or salts with organic carboxylic acids or sulfonic acids, such as acetic acid, citric acid, benzoic acid, maleic acid, fumaric acid, tartaric acid, methanesulfonic acid and p-toluenesulfonic acid. The present invention also encompasses compounds containing both acidic groups and basic groups, which can be present in the form of inner salts, zwitterions or betaines.
Salts can be obtained from the compounds of formula I by customary processes known to one of ordinary skill in the art, for example, by combining the compounds of formula I with an organic or inorganic acid or base in a solvent or diluent, or from other salts by anion exchange or cation exchange.
The compounds of formula I can be present in stereoisomeric forms. With respect to each asymmetric centers in the compounds of formula I, independently of any other asymmetric center, it is possible for the S configuration or the R configuration to be present or R/S mixtures to be present. Thus, the asymmetric carbon atom to which the residue R2 is bonded can have the R configuration or S configuration or the compound of formula I can be present as an R/S mixture with respect to this carbon atom. Likewise, the asymmetric carbon atom to which the group A and the imidazolidine ring are bonded can have the R configuration or S configuration or the compound of formula I can be present as an R/S mixture with respect to this carbon atom. All other asymmetric carbon atoms can likewise have the R configuration or the S configuration, or the compound of formula I can be present as an R/S mixture with respect to each of these carbon atoms. In R/S mixtures the individual stereoisomers can be present in any ratio including a ratio of 1:1.
The invention includes all possible stereoisomers of the compounds of formula I, for example, pure or largely pure enantiomers, pure or largely pure diastereomers and mixtures of two or more stereoisomeric forms (e.g., mixtures of enantiomers and/or diastereomers) in all ratios. The invention thus relates to enantiomers in enantiomerically pure form, both as levorotatory and as dextrorotatory antipodes, in the form of racemates and in the form of mixtures of the two enantiomers in all ratios. The invention likewise relates to diastereomers in diastereomerically pure form and in the form of mixtures in all ratios. Examples of individual stereoisomers, which are comprised by the invention, are the compounds of formulae Ia, Ib, Ic and Id. 
The preparation of individual stereoisomers, if desired, can be carried out by use of stereochemically uniform starting substances in the synthesis, by stereoselective synthesis or by separation of a mixture according to customary methods (e.g., by chromatography or crystallization, and in the case of enantiomers, by chromatography on chiral phases). If appropriate, a derivatization can be carried out before a separation of stereoisomers. The separation of a stereoisomer mixture can be carried out at the stage of the compounds of formula I or at the stage of a starting substance or an intermediate in the course of the synthesis.
The compounds of formula I can contain mobile hydrogen atoms, i.e., they can be present in various tautomeric forms. The present invention comprises all tautomers of the compounds of formula I. The present invention also encompasses solvates and addition compounds or adducts of compounds of formula I, for example adducts with water, i.e., hydrates, or adducts with alcohols or amines. The invention further comprises derivatives of compounds of formula I (e.g., esters, amides, prodrugs, other physiologically acceptable derivatives), and active metabolites of compounds of formula I.
One embodiment encompasses prodrugs of the compounds of formula I, which in vitro are not necessarily pharmacologically active, but which in vivo and under physiological conditions are converted into active compounds of formula I. Suitable prodrugs of the compounds of formula I (i.e., chemically modified derivatives of the compounds of formula I having properties improved in a desired manner), are known to one of ordinary skill in the art. More detailed information regarding prodrugs is found, for example, in Fleisher et al., Advanced Drug Delivery Reviews, 19:115 (1996); Design of Prodrugs, H. Bundgaard, Ed., Elsevier, 1985; H. Bundgaard, Drugs of the Future 16:443(1991). Suitable prodrugs of the compounds of formula I are preferably ester prodrugs, amide prodrugs, aldehyde prodrugs and alcohol prodrugs of carboxylic acid groups (e.g., a carboxylic acid group representing the group E). The compounds of formula I, wherein the group E is hydroxymethyl, alkoxymethyl or formyl and which exhibit VLA-4 antagonism in vivo are prodrugs of the compounds of formula I wherein the group E is hydroxycarbonyl. Examples of ester prodrugs and amide prodrugs are (C1-C4)-alkyl esters (e.g., methyl esters, ethyl esters, isopropyl esters, or isobutyl esters), substituted alkyl esters (e.g., hydroxyalkyl esters, acyloxyalkyl esters, aminoalkyl esters, acylaminoalkyl esters, or dialkylaminoalkyl esters), unsubstituted amides or Nxe2x80x94(C1-C4)-alkylamides (e.g., methylamides or ethylamides).
Examples of compounds of formula I are the following compounds of formulae Ie and If. The compounds of formulae Ie and If have the S configuration on the carbon atom which carries the group A; the S configuration on the carbon atom which carries the group R2 if R2 is phenyl or pyridyl; and have the R configuration on the carbon atom which carries the group R2 if R2 is methyl. The present invention also relates to the physiologically acceptable salts of the compounds of formulae Ie and If, for example, metal salts or salts with organic ammonium cations of compounds of formulae Ie and If which contain a carboxylic acid group, or acid additions salts of compounds of formulae Ie and If which contain pyridyl residues (e.g., hydrochlorides).
The individual structural elements in the compounds of formula I preferably have the following meanings, which they can have independently of one another.
R2 is preferably (C1-C4)-alkyl, which can be substituted by one or more fluorine atoms; or pyridyl; or unsubstituted phenyl; or phenyl, which is substituted by a methylenedioxy residue or an ethylenedioxy residue; or phenyl, which is substituted by one or two (C1-C4)-alkoxy groups. The alkyl group representing R2, which can optionally be substituted by fluorine, is preferably selected from the group consisting of methyl, ethyl, isopropyl, trifluoromethyl and 2,2,2-trifluoroethyl. The alkoxy substituents in a phenyl group representing R2 are preferably methoxy groups. More preferably, R2 is selected from the group consisting of methyl, pyridyl, unsubstituted phenyl, phenyl substituted by a methylenedioxy residue or an ethylenedioxy residue, and phenyl substituted by one or two methoxy groups. Most preferably, R2 is selected from the group consisting of methyl, unsubstituted phenyl and pyridyl.
R3 and R4 can be identical or different. Preferably, R3 and R4 are identical. In one embodiment, R3 and R4 are both methyl. In another embodiment, R3 and R4 are both trifluoromethyl.
An alkyl group representing R5, which can be substituted by one or more fluorine atoms, is preferably a methyl group, ethyl group or trifluoromethyl group. Preferably, R5 is (C1-C4)-alkyl, which can be substituted by one or more fluorine atoms. More preferably, R5 is methyl or trifluoromethyl, and most preferably, methyl.
R6 is preferably hydroxyl, (C1-C6)-alkoxy, phenyl-(C1-C4)-alkoxy, phenyloxy or amino (NH2) and more preferably hydroxyl, (C1-C6)-alkoxy or amino. R is even more preferably hydroxyl or (C1-C6)-alkoxy, and most preferably hydroxyl or (C1-C4)-alkoxy, in particular hydroxyl.
R7 is preferably hydrogen or (C1-C3)-alkyl, more preferably hydrogen or methyl, and most preferably hydrogen.
E is preferably xe2x80x94COxe2x80x94R6, xe2x80x94COxe2x80x94H, xe2x80x94CH2xe2x80x94OH or xe2x80x94CH2xe2x80x94OCH3, more preferably xe2x80x94COxe2x80x94R6, xe2x80x94CH2xe2x80x94OH or xe2x80x94CH2xe2x80x94OCH3, even more preferably xe2x80x94COxe2x80x94R6 or xe2x80x94CH2xe2x80x94OH, and most preferably xe2x80x94COOH, xe2x80x94COOC2H5, xe2x80x94COOiC3H7 or xe2x80x94CH2xe2x80x94OH, in particular xe2x80x94COOH.
In other embodiments of the invention, Z is sulfur or oxygen.
In other embodiments of the present invention, A is the isobutyl residue (2-methylpropyl residue, i.e., (CH3)2CHxe2x80x94CH2xe2x80x94) or cyclopropylmethyl residue (i.e., cyclopropyl-CH2xe2x80x94). In other embodiments of the present invention, R1 is hydrogen or methyl.
The present invention encompasses compounds of formula I having a uniform configuration on one or more chiral centers, including, for example, on the carbon atom carrying the residue R2, and/or on the carbon atom carrying the residue A and the imidazolidine residue. Preferred compounds of formula I have a uniform or essentially uniform configuration on one or more chiral centers, either the R configuration or the S configuration, but are not present as an R/S mixture. However, the individual chiral centers in these compounds of formula I can, independently of one another, have the R or S configuration and have identical or different configurations. More preferred compounds of formula I are those wherein the carbon atom carrying the residue A and the imidazolidine residue is present in the S configuration, i.e., in the configuration with respect to this stereocenter which is shown in formulae Ia and Ib. More preferred compounds of formula I also include those wherein the carbon atom carrying the group R2 is present in the configuration shown in formulae Ia and Ic. If R2, for example, is phenyl, substituted phenyl or pyridyl in these more preferred compounds, the carbon atom carrying the group R2 has the S configuration. Alternatively, if R2 is methyl, ethyl or isobutyl in these more preferred compounds the carbon atom carrying the group R2 has the R configuration. Most preferred compounds of formula I are those in which the two above-mentioned stereocenters are present in the configurations shown in formula Ia.
Preferred compounds of formula I include compounds having all combinations of residues as described herein. Examples of preferred compounds are, for example, compounds in which, simultaneously, R1, R3, R4 and R5 are methyl and A is isobutyl; compounds in which, simultaneously, R1, R3, R4 and R5 are methyl and A is cyclopropylmethyl; compounds in which, simultaneously, R1 is methyl, R3 and R4 are trifluoromethyl, R5 is methyl and A is isobutyl; compounds in which, simultaneously, R1 is methyl, R3 and R4 are trifluoromethyl, R5 is methyl and A is cyclopropylmethyl; compounds in which, simultaneously, R1 is hydrogen, R3, R4 and R5 are methyl and A is isobutyl; compounds in which, simultaneously, R1 is hydrogen, R3, R4 and R5 are methyl and A is cyclopropylmethyl; compounds in which, simultaneously, R1 is hydrogen, R3 and R4 are trifluoromethyl, R5 is methyl and A is isobutyl; or compounds in which, simultaneously, R1 is hydrogen, R3 and R4 are trifluoromethyl, R5 is methyl and A is cyclopropylmethyl, and the other groups have the general or preferred, or specific meanings defined herein.
Another preferred embodiment of the invention comprises, for example, compounds of formula I, wherein
A is cyclopropylmethyl- or isobutyl;
E is xe2x80x94COxe2x80x94R6 or xe2x80x94CH2xe2x80x94OH;
Z is oxygen;
R1 is hydrogen or methyl;
R2 is pyridyl, unsubstituted phenyl, phenyl substituted by a methylenedioxy residue or an ethylenedioxy residue, phenyl substituted by one or two (C1-C4)-alkoxy groups, or (C1-C4)-alkyl which can be substituted by one or more fluorine atoms;
R3 and R4 are methyl;
R5 is methyl;
R6 is hydroxyl, (C1-C6)-alkoxy, phenyl-(C1-C4)-alkoxy, phenyloxy or amino;
in all their stereoisomeric forms and mixtures thereof in all ratios,
and their physiologically acceptable salts.
Another preferred embodiment of the invention comprises, for example, compounds of formula I, wherein
A is cyclopropylmethyl- or isobutyl;
E is xe2x80x94COOH, xe2x80x94COOC2H5, xe2x80x94COOiC3H7 or xe2x80x94CH2xe2x80x94OH;
Z is oxygen;
R1 is methyl;
R2 is pyridyl, unsubstituted phenyl, phenyl substituted by a methylenedioxy residue or an ethylenedioxy residue, phenyl substituted by one or two methoxy groups, or (C1-C4)-alkyl which can be substituted by one or more fluorine atoms;
R3 and R4 are methyl;
R5 is methyl;
in all their stereoisomeric forms and mixtures thereof in all ratios,
and their physiologically acceptable salts.
Another more preferred embodiment of the invention comprises, for example, compounds of formula I, wherein
A is cyclopropylmethyl- or isobutyl;
E is xe2x80x94COOH, xe2x80x94COOC2H5, xe2x80x94COOiC3H7 or xe2x80x94CH2xe2x80x94OH;
Z is oxygen;
R1 is methyl;
R2 is unsubstituted phenyl, pyridyl, methyl or 2,2,2-trifluoroethyl;
R3 and R4 are methyl;
R5 is methyl;
in all their stereoisomeric forms and mixtures thereof in all ratios,
and their physiologically acceptable salts.
Another more preferred embodiment of the invention comprises, for example, compounds of formula I, wherein
A is cyclopropylmethyl- or isobutyl;
E is xe2x80x94COOH, xe2x80x94COOC2H5, xe2x80x94COOiC3H7 or xe2x80x94CH2xe2x80x94OH;
Z is oxygen;
R1 is methyl;
R2 is unsubstituted phenyl, pyridyl or methyl;
R3 and R4 are methyl; R5 is methyl;
in all their stereoisomeric forms and mixtures thereof in all ratios,
and their physiologically acceptable salts.
All above definitions of subgroups of the compounds of formula I apply analogously for compounds of formula I, wherein R3 and R4 are both trifluoromethyl instead of methyl. Thus, for example, more preferred compounds are also compounds of formula I, wherein
A is cyclopropylmethyl- or isobutyl;
E is xe2x80x94COOH, xe2x80x94COOC2H5, xe2x80x94COOiC3H7 or xe2x80x94CH2xe2x80x94OH;
Z is oxygen;
R1 is methyl;
R2 is unsubstituted phenyl, pyridyl or methyl;
R3 and R4 are trifluoromethyl; R5 is methyl;
in all their stereoisomeric forms and mixtures thereof in all ratios,
and their physiologically acceptable salts.
The compounds of formula I can be prepared, for example, by condensation of a compound of formula II 
with a compound of formula III, 
where in formulae II and III the groups A, E, Z, R1, R2, R3, R4 and R5 are as defined hereinabove, or alternatively, functional groups can be present in these groups in protected form or in the form of precursors, and where G is hydroxycarbonyl, (C1-C6)-alkoxycarbonyl or activated carboxylic acid derivatives such as, for example, acid chlorides or active esters.
In the condensation of the compounds of formulae II and III, it is generally necessary that a carboxylic acid group, which is present but not involved in the condensation reaction, is protected by a reversible protective group and then is present, for example, in the form of a suitable (C1-C6)-alkyl ester (e.g., tert-butyl ester) or the benzyl ester. In the preparation of compounds of formula I, wherein the group E is a hydroxycarbonyl group or a derivative of a hydroxycarbonyl group, the residue E in the compounds of formula III can first be a hydroxycarbonyl group present in protected form and then, after the condensation of the compounds of formulae II and III, the hydroxycarbonyl group can be liberated and/or the desired final group E can be synthesized in one or more further steps.
Functional group precursors are groups that can be converted into a desired functional group using typical synthetic processes known to one of ordinary skill in the art. For example, a cyano group, which can be converted into a carboxylic acid group by hydrolysis, can be designated as a precursor for the carboxylic acid group. An alcohol group, which can be oxidized to an aldehyde group, can be designated as a precursor for the aldehyde group. Examples of protective groups, which may be introduced before carrying out a reaction or a reaction sequence and are later removed again, have already been described herein.
The coupling methods of peptide chemistry, which are well known to one of ordinary skill in the art, are advantageously used in the condensation of the compounds of formulae II and III (see, for example, Houben-Weyl, Methoden der Organischen Chemie [Methods of Organic Chemistry], Volume 15/1 and 15/2, Georg Thieme Verlag, Stuttgart, 1974). Possible condensing agents or coupling reagents are, for example, carbonyldiimidazole, carbodiimides (e.g., dicyclohexylcarbodiimide (DCC) or diisopropylcarbodiimide), O-((cyano(ethoxycarbonyl)methylene)amino)xe2x80x94N,N,Nxe2x80x2,Nxe2x80x2-tetramethyluronium tetrafluoroborate (TOTU) or propylphosphonic anhydride (PPA). The condensations can be carried out under standard conditions well known to one of ordinary skill in the art. In general, the condensations are carried out in an inert solvent or diluent, (e.g., an aprotic solvent, such as N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF) or dimethoxyethane (DME)). Depending on the condensation carried out in the individual case, it may be advantageous to add a base, such as a tertiary amine or auxiliary reagents, such as an N-hydroxy compound (e.g., 1-hydroxybenzotriazole (HOBT)). The work-up of the reaction mixture and a purification of the product can be carried out according to customary standard processes known to one of ordinary skill in the art. After condensation, any protective groups present are removed by methods known to one of ordinary skill in the art, including hydrogenation, hydrolysis and acid work-up. For example, benzyl groups in benzyl esters can be removed by catalytic hydrogenation, or protective groups of the tert-butyl type can be removed by treatment with a suitable acid. The preparation of the compounds of formula I also can be carried out, for example, by synthesizing the compounds stepwise on a solid phase using customary methods known to one of ordinary skill in the art, and it is possible to introduce individual structural elements of the molecule in different sequences.
The amino compounds of formula III are commercially available or can be synthesized, according to or analogously to well-known standard processes, from commercially available starting compounds or starting compounds that are obtainable according to or analogously to literature procedures. For example, optically active 3-substituted 3-aminopropionic acids of formula III or their esters(e.g., 3-phenyl-3-aminopropionic acid esters) can be prepared from the corresponding 3-substituted acrylic acids that are obtainable from their corresponding aldehydes. The 3-substituted acrylic acids are converted, by reaction with oxalyl chloride, into the acid chlorides, which further are converted, by reaction with an alcohol, into the esters(e.g., using tert-butanol to convert acid chlorides into the tert-butyl esters). To form the amino compound, the esters are then reacted with the lithium salt of an optically active amine (e.g., the lithium salt of (R)-(+)-N-benzyl-N-(1-phenylethyl)amine), and then the benzyl group and the phenylethyl group in the 3-substituted tert-butyl 3-(N-benzyl-N-(1-phenylethyl)amino)propionate obtained are removed by catalytic hydrogenation. For the preparation of compounds of formula III, wherein E is the hydroxymethyl group CH2OH or an etherified hydroxymethyl group, it is possible to employ 3-substituted 3-aminopropanols or their ethers in the condensation reaction. The 3-substituted 3-aminopropanols or their ethers are obtainable from the 3-substituted 3-aminopropionic acids or their esters by reduction of the acid group or the ester group (e.g., from the ethyl ester or tert-butyl ester) using lithium aluminum hydride or lithium aluminum hydride/aluminum trichloride.
Compounds of formula II can be prepared, for example, by first reacting compounds of formula IV 
in a Bucherer reaction (e.g., with ammonium carbonate and potassium cyanide) to give compounds of formula V 
which further are reacted with an alkylating reagent of the formula LGxe2x80x94CHAxe2x80x94G, which introduces the residue of the formula xe2x80x94CHAxe2x80x94G into the molecule, to give compounds of formula VI, 
where A, R3, R4 and G are defined as indicated above. The reaction of compounds of formula VI with a second alkylating reagent of formula VII, 
wherein Z, R1 and R5 are defined as indicated above, gives the corresponding compounds of formula II. The group LG is a nucleophilically substitutable leaving group, for example halogen (e.g., chlorine or bromine), or sulfonyloxy (e.g., tosyloxy, methylsulfonyloxy or trifluoromethylsulfonyloxy).
Compounds of formula II also can be prepared, for example, by initially reacting a compound of formula VI with a reagent of the formula 4xe2x80x94(PGxe2x80x94NH)xe2x80x94C6H3(OR5)xe2x80x94CH2xe2x80x94LG, wherein LG is a nucleophilically substitutable leaving group as described herein, to give a compound of formula VIII, 
where the meanings indicated above apply for A, G, R3, R4 and R5 and PG is an amino protective group(e.g., tert-butoxycarbonyl or benzyloxycarbonyl). After removal of the protective group PG, the compounds of formula II are obtained by reaction of the resulting amino group H2N with phenyl isocyanate, phenyl isothiocyanate, 2-methylphenyl isocyanate or 2-methylphenyl isothiocyanate. Similar to the compounds of formula VIII, compounds can be prepared and employed in the synthesis, wherein the group PGxe2x80x94NHxe2x80x94 in formula VIII is replaced by a precursor for an amino group, which is then converted into an amino group in a further reaction step. For example, a compound of formula VI can initially be reacted with a nitro compound of the formula 4xe2x80x94O2Nxe2x80x94C6H3(OR5)xe2x80x94CH2xe2x80x94LG to give a compound corresponding formula VIII and the nitro group can further be converted into the amino group (e.g. by catalytic hydrogenation). Thereafter, the amino group can be converted into the desired compound of formula II by reaction with phenyl isocyanate, phenyl isothiocyanate, 2-methylphenyl isocyanate or 2-methylphenyl isothiocyanate.
In general, each step in the preparation of the compounds of formula I can be carried out according to or analogously to known methods familiar to one of ordinary skill in the art. Depending on each particular synthesis, it may be appropriate to temporarily block functional groups, which could lead to side reactions or undesired reactions, by means of a protective group strategy suited to the specific synthesis problem. Such a procedure, which is known to one of ordinary skill in the art, may be applied in any step of the synthesis of the compounds of formula I.
Compounds of formula I also can be obtained by reacting N-substituted amino acids or preferably of their esters, such as methyl esters, ethyl esters, tert-butyl esters or benzyl esters, for example the amino acid methyl esters of formula IX, 
wherein Z, R1, R3, R4 and R5 are defined as indicated above, with isocyanates of formula X, 
wherein A, E and R2 are defined as indicated above. The amino acid methyl esters of formula IX and other esters and the respective amino acids are obtainable according to standard processes. The isocyanates of formula X are obtainable according to standard processes from the corresponding compounds which instead of the isocyanate group contain an H2N group. The reaction of the compounds of formulae IX and X provides urea derivatives of formula XI, 
wherein R1, R2, R3, R4, R5, Z, E and A are defined as indicated above. The compounds of formula XI then can be cyclized by heating with acids to give compounds of formula I. The cyclization of the compounds of formula XI to compounds of formula I also can be carried out by treatment with bases in inert solvents (e.g. by treatment with sodium hydride in an aprotic solvent, such as dimethylformamide). During the reactions, as explained above, functional groups can be present in protected form.
Compounds of formula I also can be obtained by reacting a compound of formula IX with an isocyanate of formula XII 
wherein A has the meanings indicated above and Q, for example, is an alkoxy group (e.g., a (C1-C4)-alkoxy group, such as methoxy, ethoxy or tert-butoxy), or a (C6-C14)-aryl-(C1-C4)-alkoxy group (e.g., benzyloxy). In this reaction, a compound of formula XIII is obtained, 
wherein A, Q, Z, R1, R3, R4 and R5 are defined as indicated above The compound of formula XIII then is cyclized by reaction with an acid or a base, as described above for the cyclization of the compounds of formula XI, to a compound of formula XIV, 
wherein A, Q, Z, R1, R3, R4 and R5 are defined as indicated above. The group COxe2x80x94Q in the compound of formula XIV may be converted into the carboxylic acid group COOH, for example, by hydrolysis. The conversion of the group COxe2x80x94Q into the group COOH also can be carried out simultaneously with the cyclization if the cyclization of the compound of formula XIII to the compound of formula XIV is carried out using an acid. A compound of formula I is obtained by subsequent coupling with a compound of formula III, as described above for the coupling of the compounds of formulae II and III. Functional groups can be present in protected form or in the form of precursors in this synthetic process.
A further method for preparing compounds of formula I is, for example, the reaction of compounds of formula XV, 
for which the definitions indicated above apply, with phosgene or other chemical equivalents thereof (analogously to S. Goldschmidt and M. Wick, Liebigs Ann. Chem., 575:217 (1952) and C. Tropp, Chem. Ber., 61:1431 (1928)).
Compounds of formula I also can be prepared by coupling a compound of formula XVI, 
with a compound of formula XVII, 
to give a compound of formula XVIII 
wherein A, R3 and R4 have the meanings indicated above, PG is an amino protective group (e.g., a benzyloxycarbonyl group) and Qxe2x80x2 is a protected carboxylic acid hydroxyl group(e.g., an alkoxy group, such as tert-butoxy) in formulae XVI, XVII and XVIII. The protective group PG in the compound of formula XVIII then can be removed selectively from the amino group, for example, by hydrogenation in the case of a benzyloxycarbonyl group, and by introduction of a CO group to facilitate a ring closure, giving a compound of formula XIX is obtained 
wherein A, R3, R4 and Qxe2x80x2 have the meanings indicated above. It is possible to use, for example, phosgene or a phosgene equivalent, such as diphosgene (analogously to the reaction of the compounds of formula XV explained above), in the step of introducing the carbonyl group. As an intermediate, it is possible, for example, for an isocyanate to occur or to be prepared specifically, in the conversion of the compound of formula XVIII into the compound of formula XIX. The conversion of the compound of formula XVIII into the compound of formula XIX can be carried out in one or more steps. For example, the carbonyl group initially can be introduced and then the cyclization can be carried out, in a separate step, in the presence of a base such as sodium hydride as described for the cyclizations mentioned above. Compounds of formula XVIII, wherein PG is the benzyloxycarbonyl group also can be converted directly into compounds of formula XIX, without a synthetic building block, such as phosgene being employed for the introduction of the carbonyl group. If compounds of formula XVIII, wherein PG is benzyloxycarbonyl, are treated with a base (e.g., sodium hydride), the compounds of formula XIX can be obtained directly. The compounds of formula XIX then can be alkylated, as explained above for the compounds of formula VI, on the NH group using a reagent of formula VII and the desired compounds of formula I can be synthesized, as described above for the compounds of formulae VI and II, after conversion of the protected carboxylic acid group COxe2x80x94Qxe2x80x2 into the carboxylic acid group COOH. Functional groups can be present in protected form or in the form of precursors in this synthetic process.
In addition, compounds of formula I can be prepared by firstly reacting a compound of formula XX 
with an isocyanate of formula XII to give a compound of formula XXI, 
wherein A, R3, R4, Q and Qxe2x80x2 in formulae XX and XXI have the meanings indicated above. The compound of formula XXI then is cyclized by treating with a strong acid (e.g., semiconcentrated hydrochloric acid) to give a compound of formula XXII. 
Compounds of formula XXII also can be prepared starting from a compound of formula XVIII, wherein A, R3, R4 and Qxe2x80x2 have the meanings indicated; and PG is an alkoxycarbonyl group (e.g., (C1-C4)-alkoxycarbonyl), an (C6-C14)-aryl-(C1-C4)-alkoxycarbonyl group (e.g., phenyl-(C1-C4)-alkoxycarbonyl), or an (C6-C14)-aryloxycarbonyl group (e.g., phenyloxycarbonyl). This starting compound of formula XVIII is converted, by liberating the protected carboxylic acid group COxe2x80x94Qxe2x80x2, into a compound of formula XVIII, wherein COxe2x80x94Qxe2x80x2 is the free carboxylic acid group COxe2x80x94OH; PG is (C1-C4)-alkoxycarbonyl, (C6-C14)-aryl-(C1-C4)-alkoxycarbonyl or (C6-C14)-aryloxycarbonyl; and A, R3 and R4 have the meanings indicated above. The obtained compound of formula XVIII is cyclized to the compound of formula XXII by reaction with a base (e.g., sodium carbonate).
Compounds of formula IIa, 
wherein A, Z, R1, R3, R4 and R5 have the meanings indicated above, then can be obtained by reacting the compounds of formula XXII with an alkylating reagent of formula VII in the presence of excess base (e.g., in the presence of an excess of n-butyllithium), and then acidifying. The 4-(3-arylureido)benzyl group or 4-(3-arylthioureido)benzyl group also can be introduced stepwise into the compounds of formula XXII, which is analogous to the preparation of the compounds of formula VIII and the compounds of formula II obtained therefrom.
Compounds of formula I, wherein the residues R3 and R4 are trifluoromethyl, advantageously can be prepared by reacting an isonitrile of formula XXIII with 2-tert-butoxy-4,4-bis(trifluoromethyl)-1,3-oxazabuta-1,3-diene of formula XXIV to give a compound of formula XXV, 
where A and Q have the meanings indicated above. For example, the group C(xe2x95x90O)xe2x80x94Q is an ester group and Q is alkoxy, such as (C1-C4)-alkoxy (e.g., methoxy, ethoxy and tert-butoxy) or (C6-C14)-aryl-(C1-C4)-alkoxy (e.g., benzyloxy). The reaction of the compounds of formulae XXIII and XXIV to give the compounds of formula XXV is advantageously carried out in a hydrocarbon or ether as a solvent, for example in benzene or toluene, with warming, for example, to temperatures of from about 40xc2x0 C. to about 80xc2x0 C., for example to about 60xc2x0 C.
The isonitriles (isocyanides) of formula XXIII can be obtained from the corresponding amino carboxylic acid esters of the formula H2Nxe2x80x94CHAxe2x80x94C(xe2x95x90O)xe2x80x94Q, wherein A and Q have the meanings indicated above, using standard methods known to one of ordinary skill in the art. Advantageously, the amino carboxylic acid ester of the formula H2Nxe2x80x94CHAxe2x80x94C(xe2x95x90O)xe2x80x94Q initially is converted into the N-formylamino acid ester of the formula HC(xe2x95x90O)xe2x80x94NHxe2x80x94CHAxe2x80x94C(xe2x95x90O)xe2x80x94Q by reaction with a reactive formic acid ester (e.g., cyanomethyl formate), which then is converted, for example, by reaction with phosgene or a phosgene equivalent (e.g., diphosgene or triphosgene) in the presence of a tertiary amine (e.g., triethylamine) into the isocyanide of formula XXIII. The 2-tert-butoxy-4,4-bis(trifluoromethyl)-1,3-oxazabuta-1,3-diene of formula XXIV is obtainable, according to the process described by Steglich et al., Chemische Berichte, 107:1488 (1974), from tert-butyl carbamate ((CH3)3Cxe2x80x94Oxe2x80x94COxe2x80x94NH2) and anhydrous hexafluoroacetone, and subsequent treatment of the initially obtained 2-tert-butoxycarbonylamino-2-hydroxy-1,1,1,3,3,3-hexafluoropropane with trifluoroacetic anhydride in the presence of a base, such as quinoline.
The compounds of formula XXV then can be alkylated, for example, with compounds of formula VII, at the NH group to give compounds of formula XIV. If desired, the ester group COxe2x80x94Q in the compounds of formula XIV may be converted into the carboxylic acid group COxe2x80x94OH, and further reacted with compounds of formula III to yield compounds of formula I as described above. In the compounds of formula XXV, it is also possible to convert the ester group COxe2x80x94Q into the carboxylic acid group COxe2x80x94OH using standard processes known to one of ordinary skill in the art and further to convert the obtained compound of formula XXII, as described above, into a compound of formula IIa by reacting the compound of formula XXII with an alkylating reagent of formula VII in the presence of excess base. The compound of formula IIa may be reacted with a compound of formula III to yield a compound of formula I. The 4-(3-arylureido)benzyl group or 4-(3-arylthioureido)benzyl group also can be introduced stepwise into the compounds of formula XXV using a process analogous to the preparation of the compounds of formula VIII described above and the compounds of formula II or IIa obtained therefrom. Functional groups can be present in protected form or in the form of precursors in this synthetic process.
The compounds of formula I, wherein E, for example, is hydroxycarbonyl or hydroxymethyl, can be converted into compounds of formula I, wherein E has other meanings, or into other prodrugs or derivatives of the compounds of formula I using standard methods known to one of ordinary skill in the art. Thus, the compounds of formula I, wherein E is hydroxycarbonyl, can be esterified using the appropriate alcohols (e.g., in the presence of a condensing reagent, such as DCC) to form the corresponding ester. In addition the compounds of formula I, wherein E is hydroxycarbonyl, can be alkylated with alkyl halides (e.g., alkyl chlorides or alkyl bromides), such as acyloxyalkyl halides, to give compounds of formula I, wherein E is acyloxyalkoxy-COxe2x80x94. Compounds of formula I, wherein E is hydroxycarbonyl, can be converted into amides using ammonia or organic amines in the presence of a condensing reagent. In addition, compounds of formula I, wherein E is COxe2x80x94NH2, advantageously can be obtained on the solid phase by coupling the compound, wherein E is COOH, in the presence of a condensing agent, such as TOTU to Rink amide resin, and then removing it from the resin by treating with trifluoroacetic acid. Compounds of formula I, wherein E is the hydroxymethyl group, CH2OH can be etherified on the hydroxymethyl group using methods known to those of ordinary skill in the art. Compounds of formula I, wherein E is CH2OH, can be converted into compounds of formula I, wherein E is the aldehyde group xe2x80x94COxe2x80x94H, using methods known to those of ordinary skill in the art that pertain to the selective oxidation of alcohols to aldehydes, for example using sodium hypochlorite in the presence of 4-acetamido-2,2,6,6-tetramethylpiperidin-1-oxyl (4-acetamido-TEMPO).
Compounds of formula I, wherein R5 is hydrogen also can be prepared by carrying out an ether cleavage with compounds of formula I, wherein R5 is methyl. For example, a methoxy group representing R5O can be converted into a hydroxyl group by treatment with boron tribromide.
The compounds of formula I are valuable pharmaceutical active compounds that are suitable, for example, for the treatment of inflammatory diseases, allergic diseases or asthma. The compounds of formula I and their physiologically acceptable salts and derivatives can be administered to animals, preferably mammals, and more preferably humans, as pharmaceuticals for the treatment of disease conditions. The term treatment is generally understood to mean both the therapy of acute or chronic disease symptoms, as well as the prophylaxis or prevention of disease symptoms, i.e., for example, the prevention of acute allergic or asthmatic disease symptoms or the prevention of myocardial infarct or of myocardial reinfarct in appropriate patients. The compounds of formula I and their salts and derivatives can be administered on their own, in mixtures with one another or in the form of pharmaceutical preparations, which allow enteral or parenteral administration and which comprise an efficacious dose of at least one compound of formula I and/or its physiologically acceptable salts and/or derivatives and a pharmaceutically acceptable carrier.
The present invention also relates to the compounds of formula I and/or their physiologically acceptable salts and/or derivatives for use as pharmaceuticals (or as medicaments), the preparation of such pharmaceuticals, and their use in the treatment of the diseases mentioned above or below. The present invention further relates to pharmaceutical preparations (or pharmaceutical compositions) that contain an efficacious dose of at least one compound of formula I and/or its physiologically acceptable salts and/or derivatives and a pharmaceutically acceptable carrier (i.e., one or more pharmaceutically innocuous vehicles and/or additives).
The pharmaceuticals and pharmaceutical preparations can be administered systemically or locally. For example, the pharmaceuticals or pharmaceutical preparations can be administered orally in form of pills, tablets, film-coated tablets, sugar-coated tablets, granules, hard and soft gelatin capsules, powders, solutions, syrups, emulsions, suspensions or in other pharmaceutical forms. Administration, however, also can be carried out vaginally or rectally (e.g., in the form of suppositories), or parenterally or as implants (e.g., in the form of injection solutions or infusion solutions, microcapsules or rods), or topically or percutaneously (e.g., in the form of creams, ointments, powders, solutions, emulsions or tinctures), or by other methods known to one of ordinary skill in the art (e.g., in the form of nasal sprays or aerosol mixtures). Parenteral administration of solutions can occur, for example, intravenously, intramuscularly, subcutaneously, intra-articularly, intrasynovially or by other methods known to one of ordinary skill in the art.
The pharmaceutical preparations according to the invention are produced in a manner known per se, wherein the compound or the compounds of formula I and/or their physiologically acceptable salts and/or derivatives are mixed with pharmaceutically inert inorganic and/or organic vehicles and/or additives and prepared into a suitable dosage form and administration form. For the production of pills, tablets, sugar-coated tablets and hard gelatin capsules, it is possible to use, for example, lactose, cornstarch or derivatives thereof, talc, stearic acid or its salts, polyethylene glycols, etc., for soft gelatin capsules and suppositories, for example, fats, waxes, semisolid and liquid polyols, polyethylene glycols, natural or hardened oils etc. Suitable vehicles for the preparation of solutions (e.g., injection solutions, emulsions or syrups) are, for example, water, alcohols, glycerol, diols, polyols, sucrose, invert sugar, glucose, vegetable oils etc. and the like. Suitable vehicles for microcapsules, implants or rods are, for example, copolymers of glycolic acid and lactic acid. The pharmaceutical preparations normally contain from about 0.5 to about 90% by weight of the compounds of formula I and/or their physiologically acceptable salts and/or derivatives. The amount of active compound of formula I and/or its physiologically acceptable salts and/or derivatives in the pharmaceutical preparations is normally from about 0.2 mg to about 1000 mg, preferably from about 1 mg to about 500 mg. Depending on the nature of the pharmaceutical preparation, the amount of the active compound, however, also can be greater.
In addition to the active compounds and vehicles, the pharmaceutical preparations can also contain excipients or additives, for example, fillers, disintegrants, binders, lubricants, wetting agents, stabilizers, emulsifiers, preservatives, sweeteners, colorants, flavorings, aromatizers, thickening agents, diluents, buffer substances, solvents, solubilizers, agents for achieving a depot effect, salts for changing the osmotic pressure, coating agents or antioxidants. The pharmaceutical preparations can also contain two or more compounds of formula I and/or their physiologically acceptable salts and/or derivatives. In addition, the pharmaceutical preparations further can contain one or more other pharmaceutical active compounds, for example, substances having anti-inflammatory action.
The compounds of formula I or pharmaceutical preparations comprising them can be administered as aerosols (e.g., nasal aerosols or by inhalation) by using, for example, a spray, a nebulizer, a pump nebulizer, an inhalation apparatus, a metered inhaler or a dry powder inhaler. Pharmaceutical forms for administration as an aerosol can be prepared according to processes well known to one of ordinary skill in the art. For example, solutions or dispersions of the compounds of formula I in water, water/alcohol mixtures or suitable saline solutions can be employed using customary additives (e.g., benzyl alcohol or other suitable preservatives, absorption enhancers for increasing the bioavailability, solubilizers, dispersants and others), and, if appropriate, customary propellants (e.g., chlorofluorocarbons and/or fluorocarbons).
Other pharmaceutical active compounds which can be contained in the pharmaceutical preparations according to the invention in one or more pharmaceutical preparations in addition to compounds of formula I, but with which the compounds of formula I can also be combined in other ways in the context of a combination treatment are in particular those active compounds which are suitable for the treatment, i.e., the therapy or prophylaxis, of the diseases mentioned above or below for whose treatment the compounds of formula I are suitable. The classes of the other pharmaceutically active compounds that are different from formula I include, for example, steroids, nonsteroidal antiinflammatory substances, nonsteroidal antiinflammatory acetic acid derivatives, nonsteroidal antiinflammatory propionic acid derivatives, nonsteroidal antiasthmatics, salicylic acid derivatives, pyrazolones, oxicams, leukotriene antagonists, inhibitors of leukotriene biosynthesis, cyclooxygenase inhibitors, cyclooxygenase-2 inhibitors (COX-2 inhibitors), antihistamines, H1-histamine antagonists, nonsedating antihistamines, gold compounds, xcex22 agonists, anticholinergics, muscarine antagonists, lipid-lowering agents, cholesterol-lowering agents, HMG-CoA reductase inhibitors, statins, nicotinic acid derivatives, immunosuppressants, cyclosporins, xcex2-interferons, tumor therapeutics, cytostatics, metastasis inhibitors, antimetabolites, 5-aminosalicylic acid derivatives, antidiabetics, insulins, sulfonylureas, biguanides, glitazones, xcex1-glucosidase inhibitors, and others. Examples of suitable active compounds are acetylsalicylic acid, benorilate, sulfasalazine, phenylbutazone, oxyphenbutazone, metamizole, mofebutazone, feprazone, celecoxib, rofecoxib, diclofenac, fentiazac, sulindac, zomepirac, tolmetin, indometacin, acemetacin, ibuprofen, naproxen, carprofen, fenbufen, indoprofen, ketoprofen, pirprofen, tiaprofen acid, diflunisal, flufenamic acid, meclofenamic acid, mefenamic acid, niflumic acid, tolfenamic acid, piroxicam, isoxicam, tenoxicam, nicotinic acid, prednisone, dexamethasone, hydrocortisone, methylprednisolone, betamethasone, beclomethasone, budesonide, montelukast, pranlukast, zafirlukast, zileuton, ciclosporin, cyclosporin A, rapamycin, tacrolimus, methotrexate, 6-mercaptopurine, azathioprine, interferon-beta-1a, interferon-beta-1b, 5-aminosalicylic acid, leflunomide, D-penicillamine, chloroquine, glibenclamide, glimepiride, troglitazone, metformin, acarbose, atorvastatin, fluvastatin, lovastatin, simvastatin, pravastatin, colestipol, colestyramine, probucol, clofibrate, fenofibrate, bezafibrate, gemfibrozil, ipatropium bromide, clenbuterol, fenoterol, metaproterenol, pirbuterol, tulobuterol, salbutamol, salmeterol, terbutaline, isoetharine, ketotifen, ephedrine, oxitropium bromide, atropine, cromoglycic acid, theophylline, fexofenadine, terfenadine, cetirizine, dimetindene, diphenhydramine, diphenylpyraline, pheniramine, brompheniramine, chlorpheniramine, dexchlorpheniramine, alimezain, antazoline, astemizole, azatadine, clemastine, cyproheptadine, hydroxyzine, loratidine, mepyramine, promethazine, tripelennamine, triprolidine and others.
In combination treatments, the administration of compounds of formula I together with one or more other active compounds can be carried out by administering all active compounds together in a single pharmaceutical preparation (e.g., a tablet or capsule). The present invention also relates to pharmaceutical preparations of this type, for which all explanations above correspondingly apply. The amount of the active compounds in these pharmaceutical preparations generally is chosen to contain an efficacious amount of each active compound. A combination treatment, however, also can be carried out by administering the active compounds in two or more separate pharmaceutical preparations, which can be present in a single unit or in two or more separate units. The administration of the compounds of formula I and the other active compounds can be carried out jointly or separately, as well as simultaneously or successively, in any order. The administration also can be carried out using more than one method known to one of ordinary skill in the art, for example, one active compound can be administered orally and the other by injection, inhalation or topical application. All such treatments are encompassed by the present invention.
The compounds of formula I, for example, have the ability to inhibit cell-cell interaction processes and cell-matrix interaction processes, wherein interactions between VLA-4 and its ligands play a role. The activity of the compounds of formula I can be demonstrated, for example, in an assay, wherein the binding of cells, which contain the VLA-4 receptor (e.g., of leukocytes), to ligands of this receptor is measured (e.g., to VCAM-1), which for this purpose can advantageously also be prepared by genetic engineering. Details of such assays are described below. In particular, the compounds of formula I have the ability to inhibit the adhesion and the migration of leukocytes (e.g., the adhesion of leukocytes to endothelial cells), which is controlled by the VCAM-1/VLA-4 adhesion mechanism, as explained above. In addition to being active antiinflammatories, the compounds of formula I and their physiologically tolerable salts and derivatives are generally suitable for the treatment (i.e., for the therapy and prophylaxis) of diseases that are based on the interaction between the VLA-4 receptor and its ligands or can be influenced by an inhibition of this interaction. In particular, the compounds of formula I are suitable for the treatment of diseases that are caused at least partly by an undesired extent of leukocyte adhesion and/or leukocyte migration or are connected therewith, and for whose prevention, alleviation or cure the adhesion and/or migration of leukocytes should be decreased.
The present invention also relates to the compounds of formula I and/or their physiologically acceptable salts and/or derivatives for the inhibition of the adhesion and/or migration of leukocytes or for the inhibition of the VLA4 receptor. In addition, the present invention relates to the use of the compounds of formula I and/or their physiologically acceptable salts and/or derivatives for the preparation of pharmaceuticals thereof, i.e., of pharmaceuticals for the treatment of diseases, wherein the leukocyte adhesion and/or leukocyte migration shows an undesired extent, or for the treatment of diseases, wherein VLA-4-dependent adhesion processes play a role, and to the use of the compounds of formula I and/or their physiologically acceptable salts and/or derivatives in the treatment of diseases of this type.
The compounds of formula I can be employed as antiinflammatories, in the case of inflammatory symptoms of very different cause, to prevent, reduce or suppress the undesired or harmful sequelae of the inflammation. They are used, for example, for the treatment of arthritis, rheumatoid arthritis, polyarthritis, inflammatory bowel disease (ulcerative colitis, Crohn""s disease), systemic lupus erythematosus, inflammatory diseases of the central nervous system (e.g., multiple sclerosis), or asthma or allergies (e.g., allergies of the delayed type (type IV allergy)). Furthermore, compounds of formula I are suitable for cardioprotection, for stroke protection and for the secondary prophylaxis of stroke and for the treatment of cardiovascular diseases, atherosclerosis, myocardial infarct, myocardial reinfarct, acute coronary syndrome, stroke, restenoses, diabetes, damage to organ transplants, immune diseases, autoimmune diseases, tumor growth or tumor metastasis in various malignancies, malaria and other diseases where a blocking of the integrin VLA-4 and/or an influencing of the leukocyte activity appears appropriate for prevention, alleviation or cure. A preferred use is the prevention of myocardial infarct or of myocardial reinfarct.
The dosage amounts of the compounds of formula I can vary within wide limits and is to be adjusted in each individual case in view of the individual conditions, as readily determined by those skilled in the art (e.g., physicians). Thus, the magnitude of a prophylactic or therapeutic dose of the compounds of formula I depends, for example, on the nature and severity of the disease to be treated, the condition of the patient, the compound employed, whether an acute or chronic disease condition is being treated or prophylaxis is conducted, or whether, in addition to the compounds of formula I, further active compounds may be administered. In general, oral administration of a daily dose from about 0.01 to about 100 mg/kg, preferably from about 0.1 to about 10 mg/kg (in each case mg per kg of body weight) is adequate for administration to an adult weighing about 75 kg to achieve efficacious results. For intravenous administration, the daily dose in general is from about 0.01 to about 50 mg/kg, preferably from about 0.01 to about 10 mg/kg (in each case mg per kg of body weight). The daily dose can be divided into a number of partial administrations (e.g., 2, 3, or 4), particularly in the administration of relatively large amounts. If appropriate, it may be necessary to decrease or increase the daily dose indicated, depending on individual behavior.
In addition to being pharmaceutically active compounds in human medicine and veterinary medicine, the compounds of formula I and their salts and derivatives can further be employed for diagnostic purposes (e.g., in in vitro diagnoses of cell samples or tissue samples), and as an auxiliary or as a scientific tool in biochemical investigations, wherein a blocking of VLA-4 or an influencing of cell-cell or cell-matrix interactions is desired. Furthermore, the compounds of formula I and their salts can be used as intermediates for the preparation of other compounds, particularly other pharmaceutical active compounds, which are obtainable from compounds of formula I (e.g., by modification or introduction of residues or functional groups, such as by esterification, reduction, oxidation or other transformations of functional groups).